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ABS printing...

Posted: Thu Jun 05, 2014 2:48 am
by Norm77
I have just started printing with ABS and I seem to be having problems.
They're not the same type of problems as I had with PLA.

I am using a Test Disk 25.4mm dia. x 4.7mm thick (1" x 0.185") designed
in AutoCAD.

The biggest problems seem to be the layers in the model are "delaminating".
I've worked with several temperatures for both the bed and the nozzle. I am
now up to 230 degs. at the nozzle and 90 degs. on the bed of the Orion Delta.
I know that the nozzle can be set up to 240 degs. and I will work on that
tomorrow, but in the mean time I was wondering if anyone may have some
pointers on some other settings.

I also used this Test Disk in many tests with PLA and did not
experience any layer issues concerning "delamination" to speak off.

Take care,

Norm77...

Re: ABS printing...

Posted: Thu Jun 05, 2014 3:06 am
by McSlappy
What bed surface are you printing on? Blue tape? Glue? Hairspray?

Do you have some shots of the issue?

Re: ABS printing...

Posted: Thu Jun 05, 2014 7:33 am
by guanu
since you are used to printing with pla, are you using the same slicing settings? because if you have a layer fan and it is turning on with abs, that will cause layer delamination... you want to make sure not to have a layer fan on when using abs

Guanu

Re: ABS printing...

Posted: Thu Jun 05, 2014 2:01 pm
by Norm77
To McSlappy:
Sorry I didn't include more information. It was late and I wasn't thinking. I know
how frustrating it can be to post a message and not include more information.
I'll be more careful next time. Thanks again for responding.

To guanu:
You hit the nail on the head. This time I turned off the fan and the Test Disk
plotted much better. As in the previous post I'm still using nozzle at 230 degs.
and bed at 90 degs. I think I can tweak it a little more, but for now it seems to
be doing ok.

One more thing - should I stay away from the 240 deg. setting on the nozzle?
Won't the heater last longer if very high temperatures are avoided? Also is
there a "life expectancy" for this heater design? Just curious.

Thanks again for your suggestions.

Norm77...

Re: ABS printing...

Posted: Thu Jun 05, 2014 2:17 pm
by Polygonhell
240's fine if it's actually 240, i.e. you've checked what the thermistor is reading against a thermocouple.
The reason the limit is set at 240ish isn't because of the heating element, it's because the PEEK part of the hotend melts at 250ish.

With resistor heating elements, guessing lifetimes is a bit of a crap shoot, they really aren't designed to run as hot as most printers run them, and a lot depends on the assembly of the hotend, if there is an airgap between the resistor and the actual heater block, they can fail very quickly, but I've also seen resistors in hotends like this last thousands of hours.

With ABS you'll find that the hotter you print the stronger the bond between layers, I find even at 230C the bond isn't very good, but you trade of the ability to print overhangs with stronger layer bonds, if you print it hot enough 240-260 you can print ABS with a fan running.